Harvey Ravages Power Generation and Transmission

08/31/2017 | Sonal Patel

Harvey—a massive weather system, which has so far killed 38 people, displaced thousands of others, and caused widespread flooding in Texas—downed 7.6-GW of generation resource capacity, along with two major 345-kV transmission lines and 85 other high-voltage transmission lines serving the Gulf Coast.

As of 1 p.m. on August 30—about four days and 18 hours since the devastating system made landfall as a category 4 hurricane—utilities serving the storm-affected areas reported more than 296,000 customers without power. Most, about 105,660, were in the Corpus Christi area served by AEP Texas, but CenterPoint Energy was also scrambling to restore power to 89,089 customers in the Houston-Galveston area. Outages also affected the rural Gulf Coast area, suburban Houston, East Texas, New Orleans, and central and eastern Louisiana.

Courtesy: EEI

Generation Outages Surge as Demand Heightens

The Electric Reliability Council of Texas (ERCOT), the entity that manages the flow of power to 24 million Texans—representing about 90% of the state’s electric load—on August 30 said the grid remained in stable condition, and its competitive markets continue to operate.

On August 30, ERCOT noted that 7,600 MW of generation resource capacity was offline and some units were operating at reduced capacity for reasons related to the storm. That figure surged upwards from 6,700 MW of capacity—“including a small percentage of renewables”—that was reported offline as of 5 p.m. on August 28. However, ERCOT said the level of generation outages “does not pose a reliability concern for the ERCOT system at this time.”

The grid entity on August 30 also noted that demand was beginning to increase as service was restored and temperatures began to rise. Electricity demand in the days since landfall has been about 20,000 MW below typical August electricity use, peaking at less than 44,000 MW on August 28 as the devastation widened, due to a combination of structural damage along the coast and cooler temperatures in much of the region. As of August 30, demand was forecast to reach between 51,000 MW and 52,000 MW.

Power plants in Harvey’s direct footprint as of August 25, 2017. Source: https://www.eia.gov/special/disruptions/

ERCOT said it could not provide information on generation resources affected by fuel type, but it may make that information public later.

ERCOT spokesperson Robbie Searcy told POWER on August 30 that the grid entity has done everything it could to keep the lights on, even though it was impossible to pinpoint the scope of the devastation. “ERCOT Operations has remained focused on overall system reliability, working closely with the transmission and generation suppliers in the region to prepare for and respond to changing conditions. That close coordination will continue throughout the restoration process,” she said.

Key to those efforts were a number of tolls in ERCOT’s control room to support situational awareness, Searcy added. Additional engineers have remained available around the clock to support operations throughout the event.

Power Sector Joins Forces to Restore Power

The Edison Electric Institute (EEI), an industry coalition of all the nation’s investor-owned power companies, lauded the power industry’s team effort to restore power in the afflicted region. As of August 30, about 10,000 mutual assistance crew workers (see sidebar, “What Is Mutual Assistance?”) from at least 21 states were assisting impacted power companies with restoration, and additional resources were ready to mobilize further assistance as needed.

Courtesy: EEI

“Responding to major events like Harvey requires significant coordination among many public and private sectors. There are interdependencies among the energy, communications, supply chain, transportation, and water and wastewater sectors. Strong industry-government coordination is critical,” noted Brian Reil in a statement on August 30. The power sector, represented by the CEO-led Electricity Subsector Coordinating Council, has had daily calls since August 25 with senior government officials to ensure that all resources can be met, the EEI noted.

What Is Mutual Assistance?

The U.S. power industry, connected by a common grid and a mission to keep the lights on, bands together to provide mutual assistance during disasters. According to the Edison Electric Institute (EEI), this voluntary partnership of companies across the country is a “hallmark of the electric power industry” serves as an effective—and crucial—restoration resource for power companies.

The EEI says that with mutual assistance, which is an essential part of contingency planning, power companies impacted by a major outage event are able to increase the size of their workforce by “borrowing” restoration workers from other companies in unaffected areas. EEI member companies work through seven regional mutual assistance groups across the country, who are ready to provide assistance when needed. When called upon, a company will send skilled restoration workers—both company employees and contractors—along with specialized equipment to help with the restoration efforts of a fellow company.

Harvey’s assault on the Gulf Coast region began on Friday. At least 70 repair crews were on the ground by Monday from other parts of Texas, Alabama, Florida, Kansas, Louisiana, and Tennessee. As of Wednesday morning, more than 10,000 workers from at least 20 states were attempting to restore power, the EEI said.

Courtesy: EEI

Harvey Knocks Out Gas Supplies, Bite Yet to Come

Harvey’s indirect impact on the nation’s power generators may yet be felt nationwide owing to a halt in natural gas production and storage operations, some analysts warned on August 30.

Courtesy: EEI

As the storm moved to the east and continued its assault on Louisiana, natural gas production restarted at hard-hit areas in South Texas, including from Eagle Ford shale gas. The Platts Analytics’ interstate pipeline sample of Eagle Ford output over the 14 days prior to the storm averaged 1.4 Bcf/d, said S&P Global Platts. During the storm, it dropped 1 Bcf/d to 0.4 Bcf/d, but the sample rebounded to 0.9 Bcf/d Wednesday.

Tres Palacios Gas Storage, an underground salt cavern natural gas storage facility in Matagorda County, Texas, was still under force majeure and remains shut as of Wednesday. The company issued a notice saying that flood waters had started to recede and personnel have gained limited access to the facility, however.

According to the Energy Information Administration, Texas averaged 18.2 billion cubic feet a day in natural gas production in 2017 through the end of May—a quarter of the nation’s lower-48 state gas production. The agency also reported natural gas storage was 45 Bcf above the five-year average as of August 18, 2017, but that is likely to decrease as a result of the storm.

—Sonal Patel is a POWER associate editor (@sonalcpatel, @POWERmagazine)

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